Indian: The Indian system places a lot of emphasis on rote learning material. The focus is on absorbing as much knowledge as you can. Consequently Indians do well in quantitative subjects (science, engineering, maths...) where covering a lot of material takes you to a higher level of skill. However, knowledge is treated as facts and immutable truths rather than ideas to be assessed critically, so young Indians don't do as well in "soft" subjects and generally poor at critical or independent thinking. Schools for the most part completely ignore personality development and social skills.
American: The American system swings in the opposite direction with a greater emphasis on soft skills and creating a more rounded individual. As more time is spent on developing character, giving students broad exposure to different subject areas there is less time and incentive to delve deeply in to any subject area. What you get are more rounded individuals with broader cross subject knowledge but then weaker in specific subject areas than Indian counterparts.
British: The British system is somewhat in the middle. In the latter years of high school there is increasing levels of specialisation so subjects can be covered in more depth. Critical analysis is also key to the system of teaching. However the softer skills and character development (at least in my time) was not really emphasised. So you end up with individuals with greater specific subject knowledge than US counterparts who study more subjects but less than Indian counterparts due to the time spent analysing & exploring ideas rather than just memorising them.
Which do I think is better? All of them have their strengths and weaknesses. Ideally you would teach all subjects to the depth that the Indian system does and include the time for critical debate, character development and soft skills. But the poor children will probably never get a holiday and end up under a lot of pressure.
So having my own children to educate this is what I have chosen to do. We are currently in India where they are studying. Knowing the weaknesses of the Indian system, my wife and I are filling in the gaps by systematically teaching our children to develop their social skills, critical analysis, debating, exercising creative skills and giving them a broad range of experiences. I believe in the US or the UK we would find it much harder to teach them greater levels of depth in their different subjects whereas the softer side is easier as parents and also benefits from our own experiences.